A computer may concurrently execute several operating systems. Each operating system may reside in its own logical partition (LPAR), with each LPAR allocated a part of a physical processor, an entire physical processor, or multiple physical processors at the computer. An underlying hypervisor (or partition manager) manages and controls the LPARs. Peripheral component interconnect (PCI) is a system input/output (I/O) bus that provides an interface that enables a processor to communicate with peripheral devices such as storage devices, display devices, etc., through the use of adapters. The hypervisor assigns PCI memory space for each adapter in the system. Each adapter may have a total base address register (BAR) space requirement from hundreds of megabytes to over a gigabyte memory. There is a need to efficiently manage available memory space in a computer system.